Extensible trestle.



Ptented Nov. 28, I899. E. c. BISHOP.

EXTENSIBLE TRESTLE.

(Application filed Max. 28, 1899.)

(No Model.)

fijd/Fzawvw m (l3, MAM/f NITED STATES PATENT OFFICE.

EDWIN C.BISHOP, OF HARTFORD, CONNECTICUT.

EXTENSIBLE TRESTLE.

SPEGIFIGATION fQrming part of Letter Patent No. 637,847, dated November28, 1899.

Application filed March 28, 1899. Serial No. 710,777. (No model.)

T0 ctZZ whom it may concern.-

Be it known that I, EDWIN C. BISHOP, a citizen of the United States,residing at Hartford, I

in the county of Hartford and State of Connecticut, have inventedcertain new and useful Improvements in Extension-Trestles, of which thefollowing is a specification.

This invention relates to those trestles provided for the use of masons,carpenters, decorators, andthe like artisans and which are extensible,so that staging may be built upon them at many different levels.

The object of this invention is to construct a very simple andconvenient trestle of this nature that will be exceedingly strong,reliable, and durable.

This invention resides in a trestle that has sections with the usualsteps or rounds so hinged together that they may be closedparallel witheach other or opened at an angle with each other, with a sliding sectionhaving ordinary steps or rounds located between the hinged sections, thehinged sections being provided with lugs and the sliding section havingshoulders adapted to be engaged by i the lugs when the trestle is in usein such manner that the greater the weight upon the trestle the firmerwill the sliding section be supported.

Figure 1 of the accompanying drawings shows a side elevation of atrestle that embodies the invention With the sliding section extendedfor use. Fig. 2 shows a front elevation of the extended trestle. Fig. 3shows a side elevation of the same trestle closed, and Fig. 4 is adetail View showing on larger scale a hinged plate and the lugs securedto the hinged sections and the shoulders of the sliding section.

The hinged sections are each built of a pair of side rails 1, made ofwood or any other desired material, with common rounds 2 extendingbetween these rails. These sections are connected near their upper endsby hingeplates 3, so that they may be spread outward and stand at anangle when in use, as shown in Fig. 1, or fold parallel for storage, asillustrated in Fig. 3. Spreading-toggles at are attached to the siderails for holding these sections open.

The sliding section, that is movable between the hinged sections, isbuilt of a pair of side rails 5, with rounds 6 extending between them.Each of the side rails of the sliding section is in the plane of theside rails of the hinged sections, and in the outside edge of the railsof the sliding section is a longitudinal groove 7. On the back of thehinge-plates are tongues 8, that project into these grooves. Thisarrangement holds the hinged plates so that the hinged sections willopen and close easily and uniformly and so that the extensible sectionwill slide smoothly and be held securely.

Secured to the beveled upper ends of the side rails of the hingedsections are lug-plates 9, that have supporting-lugs. 10, and formed inthe edges of the side rails of the sliding section are notches withsupporting-shoulders 11, of which there may be any desired number.

When the hinged sections are closed to gether,thesliding section may befreely moved between them; but when the hinged sections are opened thelugs secured to their upper ends will pass into notches belowsupportingshoulders on the edges of the side rails of the slidingsection.

When used, the sliding section is lifted to the desired heightand thenthe hinged sections are spread apart, so as to brace each other, In thisrelation they are held spread by the spreading-toggles. As the hingedsections are spread the supporting-lugs attached to their upper endsproject into notches beneath the proper supporting-shoulders on the sliding section. The supportinglugs on the hinged sections cannot work outfrom beneath the supporting-shoulders on the sliding section until thehinged sections are closed, and the hinged sections cannot again beclosed until the spreading-toggles are unlocked.

The parts of this trestle are very simple, strong, and durable. Thereare no springs or working parts that will wear, break, or become loose.The sliding section may be locked at any desired height, and staging maybe built upon any of the rounds of the hinged sections or of the slidingsection. The weight upon the sliding section, tending to cause it todrop, is sustained by the engagement of the solid shoulders of thesliding section with the strong lugs attached to the ends of the hingedsections, and these parts cannot accidentally become disengaged, for theweight upon the sliding section will tend to cause the hinged sectionsto spread at the bottom and close at the top, and this causes a closerengagement of the lugs and shoulders. By this means the greater theweight upon the extending part of the trestle the firmer will thesliding section be supported. Thus all liability of collapse is averted.

I claim as my invention-- 1. An extensible trestle having threesections, each consisting of a pair of side rails joined by rounds, withshoulders formed on the edges of the side rails of the middle sectionand lugs projecting from near the upper ends of the side rails of thetwo outer sections in position to engage with the shoulders on theadjacent side rails of the middle section, plates outside of the siderails of all three sections, and bolts passing through the plates andpivotally connecting the side rails of the two outer sections with theplates, substantially as specified.

2. An extensible trestle having three sections, each consisting of apair of side rails joined by rounds, with shoulders formed on the edgesof the side rails of the middle section and lugs projecting from nearthe upper ends of the side rails of the two outer sections in positionto engage with the shoulders on theadjacent side rails of the middlesection, plates outside of the side rails of all three sections, boltspassing through the plates and pivotally connecting the side rails ofthe two outer sections with the plates, and tongues extending from theplates into grooves in the outside of the side rails of the middlesection, substantially as specified.

EDWIN C. BISHOP.

Witnesses:

HARRY R. WILLIAMS, E. J. HYDE.

